Fields hold your application data and can be added to 
Forms.
Event scripts and a Page's Controls can interact with Fields to get and set the data they represent.
A Field has properties such as Type (Character, Integer, Date, etc), Display Type (Text, Number, Date, etc) and Length.
The 
Fields View 
in the top-right corner of the Form Editor lists all the Fields added to the Form. Clicking on a Field shows its properties in the Properties View. These properties can then be edited.
To create a new Field click 
in the Fields View. Multiple Fields can be added at once by clicking 
.